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22
Scripting concepts
Variables
Variables are containers for data. A variable might contain a number, a string, a list (or array), or
an object reference. Variables have names, and you refer to a variable by its name. To put data
into a variable, we assign the data to the variable. The file name of the current Illustrator
document or the current date are both examples of data that can be assigned to a variable.
Why not simply enter the value directly in the script rather than using a variable? When you use
a value directly the flexibility of script is reduced. By using variables the scripts you write will be
reusable in a wider variety of situations. As a script executes, it can assign data to the variables
that reflect the state of the current document and selection, for example, and then make
decisions based on the content of the variables.
In AppleScript, it is not necessary to declare your variables before assigning values to them. In
Visual Basic, however, it is considered good form to declare all of your variables before using
them with the Dim statement. Using the Dim statement assigns a value type to the variable,
which helps us keep our scripts clear and readable. Memory is also used more efficiently if
variables are declared before use. If you start your scripts in Visual Basic with the line Option
Explicit, you will be required to declare all variables before assigning data to them.
Visual Basic
Option Explicit
Dim thisNumber As Single
thisNumber = 10
Assigning values to variables is fairly simple, as shown below.
AppleScript
set thisNumber to 10
set thisString to "Hello, World!"
Visual Basic
thisNumber = 10
thisString = "Hello, World!"
Variables can also be used to store references to objects. In AppleScript, a reference is returned
when you create a new object in an Illustrator document. This returned reference points to the
12 Aug 03
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